And indeed the average sleep cycle is about 1.5 hours long. See http://www.boston.com/bostonglobe/ideas/naps/ http://www.boston.com/bostonglobe/ideas/naps/ Per

And indeed the average sleep cycle is about 1.5 hours long. See http://www.boston.com/bostonglobe/ideas/naps/ http://www.boston.com/bostonglobe/ideas/naps/ Personally I like to get up early (around 6am), go to bed when done for the day and nap when tired.